JP2903868B2 - Printing ink binder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a binder for printing inks.

[0002]

2. Description of the Related Art In recent years, with the diversification of packaging materials and the advancement of packaging technology, various types of plastic films have been developed as packaging materials. It is becoming. By the way, when a plastic film is used as a packaging material, printing is performed for decoration or surface protection of the plastic film, and the printing ink for such printing has good adhesion to these various plastic films. There is a growing demand for advanced performance.

[0003] Conventionally, polyurethane has been widely used as a binder for printing ink used for such printing ink. In general, a printing ink using polyurethane as a binder has excellent adhesive strength to polyester film and nylon film alone, but has insufficient adhesive strength to general-purpose films such as polyethylene film and polypropylene film. When printing on a film or a polypropylene film, a two-component reaction type ink in which a polyisocyanate compound is blended with polyurethane is used to supplement the adhesive strength. However, the two-pack reaction type ink has a disadvantage that a curing agent has to be blended immediately before printing, which is inconvenient to handle, and has various limitations in terms of pot life (pot life). .

[0004] Therefore, in the art, various researches and developments have been made on polyurethanes which have good adhesion to various plastic films and which can be used as a binder for one-pack type ink which does not require the incorporation of a polyisocyanate compound. And the adhesiveness is somewhat improved.

[0005]

However, for example, when the one-pack type ink is used for printing a plastic film used as a packaging base material which is subjected to a boil sterilization process, a retort sterilization process, etc. after packaging the food. However, there is a problem that such printed matter is still inferior in boil resistance and retort resistance (hereinafter referred to as boil resistance). Therefore, in the field where boil resistance and the like are required, one-component inks are difficult to use, and despite these disadvantages, two-component reactive inks still containing a polyisocyanate compound are still predominant. is the current situation.
The present invention solves the problems as described above, and provides a one-component printing ink binder having excellent adhesiveness to various plastic films such as polyester, nylon, polyethylene, and polypropylene as a substrate to be printed, and boil resistance. Aim.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to provide a binder for a one-pack type printing ink which can solve the above-mentioned problems, and as a result, have been able to print a polyurethane containing a specific glycol as a constituent component. The inventors have found that such a problem can be solved when used as a binder for ink, and have completed the present invention.

The present invention relates to a printing ink binder mainly containing a polyurethane obtained by reacting a polymer diol, a diisocyanate compound and a chain extender, wherein 2-methyl-1,3 is used as a constituent of the polyurethane. A binder for printing inks, characterized in that propanediol is used.

In the present invention, in order to solve the above problems,
2-methyl-1,3-propanediol (hereinafter referred to as MPG
Is used as a component. More specifically, it is a polyurethane using MPG as a glycol component of a polyester diol that forms a polymer diol or as a chain extender component that reacts with a diisocyanate compound, and the MPG improves the boil resistance of a binder for printing ink. Has contributed.

Next, other components in the present invention will be described. In the present invention, as described above, the above problem is solved by using a polyester diol composed of a glycol component containing MPG and a dibasic acid component as the high molecular diol component, but at least 50% by weight of the glycol component is MPG. It is good. When the content is less than 50% by weight, the boil resistance and the like are deteriorated when a one-component ink is used. The glycol component may be only MPG. In the glycol component of the polyester diol, as long as the content is less than 50% by weight, in addition to MPG, various known components generally known as the glycol component of the polyester can be used in combination. For example, ethylene glycol, diethylene glycol,
Triethylene glycol, 1,2-propanediol,
1,3-propanediol, 1,3-butanediol,
Various known saturated and unsaturated compounds such as 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, 1,4-butynediol, and dipropylene glycol. Glycols. Also,
In the present invention, in addition to the above-mentioned glycols, alkyl glycidyl ethers such as n-butyl glycidyl ether and 2-ethylhexyl glycidyl ether, and monocarboxylic acid glycidyl esters such as versatic acid glycidyl ester can also be used as one kind of glycols. further,
Up to 5 mol% of the total glycol component can be replaced by the following various polyols, for example, glycerin, trimethylolpropane, trimethylolethane,
Examples thereof include 2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, and pentaerythritol.

As the dibasic acid component, which is another component forming the polyester diol together with the above-mentioned various glycol components, various known components which are generally known as an acid component of polyester can be used as follows. . For example, adipic acid, maleic acid, fumaric acid,
Dibasic acids such as phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, and the corresponding acid anhydrides and dimer acids Is raised.

The number average molecular weight of the polyester diol comprising the glycol component containing MPG and the dibasic acid component is appropriately determined in consideration of the solubility, drying properties, blocking resistance and the like of the obtained polyurethane. 4
000, preferably in the range of 1000 to 3000. If the number average molecular weight is less than 700, the printability tends to be inferior due to the decrease in solubility, while 400
If it exceeds 0, drying properties and blocking resistance tend to decrease.

Further, as long as it does not deviate from the performance of the polyurethane of the present invention, in addition to the polyester diol of the present invention, a polymer or copolymer such as ethylene oxide, propylene oxide or tetrahydrofuran may be used as the polymer diol component. Polyether polyols, polyester polyols other than the present invention obtained by condensing a dibasic acid and a glycol component, polyester polyols obtained by ring-opening polymerization of a cyclic ester compound, other, polycarbonate polyols, polybutadiene glycols, bisphenol Various known polymer polyols generally used for the production of polyurethane, such as glycols obtained by adding ethylene oxide or propylene oxide to A, can be used in combination.

In the present invention, various known aromatic, aliphatic or alicyclic diisocyanates can be used as the diisocyanate compound. For example, 1,5
-Naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1, 4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4
-Diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate,
Dicyclohexylmethane-4,4-diisocyanate,
Typical examples thereof include 1,3-bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate, and dimer isocyanate obtained by converting a carboxyl group of dimer acid into an isocyanate group.

In the present invention, the above problem can be solved also by using MPG as a chain extender.
In this case, the amount of MPG used is preferably at least 50% by weight or more in the chain extender component. When the content is less than 50% by weight, the boil resistance and the like are deteriorated when a one-component ink is used. The chain extender component may be 100% by weight of MPG.

If the content of the chain extender component is less than 50% by weight, MPG can be used in combination with various known chain extenders, for example, ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, diethylenetriamine. , Isophoronediamine, dicyclohexylmethane-4,4'-diamine and the like. In addition, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2
Diamines having a hydroxyl group in the molecule such as -hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine and the like, and low-molecular-weight glycols described in the above-mentioned section of the polyester diols And dimer diamine in which a carboxyl group of dimer acid is converted into an amino group.

Further, if necessary, a chain terminator may be used. Examples of such a chain terminator include dialkylamines such as di-n-butylamine and alcohols such as ethanol and isopropyl alcohol. Further, if MPG is used for both the glycol component and the chain extender component of the high molecular diol, the boil resistance and the like can be further improved. In this case, however, the amounts of both used are not limited to the above ranges, but are synergistic. Any range may be used as long as the effects of the present invention can be achieved.

The method for producing the polyurethane used in the present invention is not particularly limited. For example, a polymer diol component and a diisocyanate compound are reacted under an isocyanate group excess condition, and isocyanate groups are added to both ends of the polymer diol. A two-stage process in which a prepolymer having isocyanate content (preferably 0.5 to 10%) is prepared and then reacted with a chain extender and, if necessary, a chain terminator in a suitable solvent; Any one-step method in which the components, the diisocyanate compound, the chain extender and, if necessary, the chain terminator are reacted at once in an appropriate solvent can be adopted, but in that a uniform polymer solution is easily obtained. Preferably, a two-stage method is employed. In the production of these polyurethanes, various known catalysts such as tin-based catalysts such as stannous octylate can be added.

When the polyurethane used in the present invention is produced by a two-step method, the conditions for reacting the high molecular weight diol component with the diisocyanate compound are not particularly limited, except that the isocyanate group becomes excessive. Hydroxyl group / isocyanate group is 1 / 1.2 to 1/3 in equivalent ratio.
It is preferable to carry out the reaction so as to fall within the range. In addition, the conditions for reacting the obtained prepolymer with the chain extender and the chain terminator used as required are not particularly limited, but the free isocyanate groups having at both ends of the prepolymer are equivalent to 1 equivalent. The total equivalent weight of active hydrogen capable of reacting with isocyanate groups in the chain extender is 0.5 to
It is preferably in the range of 2.0 equivalents (especially when the active hydrogen-containing group is an amino group, it is preferably in the range of 0.5 to 1.3 equivalents). When the active hydrogen is less than 0.5 equivalent, drying properties, blocking resistance, and film strength are not sufficient, and when the active hydrogen becomes excessive than 2.0 equivalents, the chain extender is unreacted. It remains as it is, and the odor tends to remain on the printed matter. In these production methods, the solvents used are usually aromatic solvents such as benzene, toluene and xylene which are well known as solvents for printing inks; methanol, ethanol, isopropanol, n-
Alcohol solvents such as butanol; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate; these may be used alone or in a mixture of two or more.

The number average molecular weight of the thus obtained polyurethane of the present invention is preferably in the range of 5,000 to 100,000. When the number average molecular weight is less than 5,000, the drying property, blocking resistance, film strength, oil resistance, etc. of the printing ink using this as a vehicle are apt to decrease, while when it exceeds 100,000, the polyurethane resin The viscosity of the solution (binder) increases, and the gloss of the printing ink tends to decrease. Further, the resin solid content concentration of the polyurethane resin solution is not particularly limited,
It may be appropriately determined in consideration of workability at the time of printing and the like.
It is practically preferable to adjust the temperature to the range of 25 ° C.

Further, in the present invention, if necessary, in addition to the polyurethane which is the main component of the present invention, the following resins may be used in combination as the binder of the present invention as auxiliary components.
For example, polyurethanes, polyamides, nitrocellulose, polyacrylates, polyvinyl chloride, copolymers of vinyl chloride and vinyl acetate, rosin-based resins, ketone resins and the like other than the present invention can be mentioned.

The binder of the present invention comprises a colorant, a solvent,
Further, if necessary, a surfactant, a wax, and other additives for improving the ink fluidity and the ink surface film are appropriately compounded and kneaded using a normal ink manufacturing apparatus such as a ball mill, an attritor, and a sand mill. A printing ink composition can be manufactured. In the printing ink composition, the compounding amount of the binder of the present invention is preferably such that the resin solid content is 3 to 20% by weight.

[0022]

According to the present invention, the one-pack type printing ink using the printing ink binder of the present invention is a printing material such as polyester,
It has the effect of exhibiting excellent adhesiveness and boil resistance to various plastic films such as nylon films, polyethylene and polypropylene.

[0023]

EXAMPLES The present invention will be described in detail below with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited to these Examples.

Production Example 1 A round bottom flask equipped with a stirrer, a thermometer, a water separator, and a nitrogen gas inlet tube was charged with 1,000 parts of 2-methyl-1,3-propanediol and 1,430 parts of adipic acid. The esterification is carried out at 200 ° C. while removing the condensed water.
Performed for 4 hours. The acid value of the polyester is 2 KOHmg /
g or less, and the degree of vacuum was gradually increased by a vacuum pump to complete the reaction. Thus the hydroxyl value 56
A polyester diol having a KOH mg / g, an acid value of 0.3 KOH mg / g and a number average molecular weight of 2,000 was obtained.

Preparation Example 2 In the same round bottom flask as in Preparation Example 1, 2-methyl-1,3
-1000 parts of propanediol and 1300 parts of adipic acid were charged, and esterification was carried out at 200 ° C for 24 hours while removing condensed water under a nitrogen stream. After confirming that the acid value of the polyester became 2 KOHmg / g or less, the degree of vacuum was gradually increased by a vacuum pump to complete the reaction. Thus, a hydroxyl value of 115 KOH mg / g and an acid value of 0.3 KOH
A polyester diol having a number average molecular weight of 1000 mg / g was obtained.

Production Example 3 In the same round bottom flask as in Production Example 1, 2-methyl-1,3
-1000 parts of propanediol and 1490 parts of adipic acid were charged, and esterification was performed at 200 ° C for 24 hours while removing condensed water under a nitrogen stream. After confirming that the acid value of the polyester became 2 KOHmg / g or less, the degree of vacuum was gradually increased by a vacuum pump to complete the reaction. Thus, a hydroxyl value of 38 KOH mg / g and an acid value of 0.5 KOHm
g / g, a polyester diol having a number average molecular weight of 3000 was obtained.

Preparation Example 4 In a round bottom flask similar to that of Preparation Example 1, adipic acid 1050 was added.
And 1,000 parts of 1,6-hexanediol, and esterification was carried out at 200 ° C. for 24 hours while removing condensed water under a nitrogen stream. 2K acid value of polyester
After confirming that the OH concentration was not more than OH mg / g, the degree of vacuum was gradually increased by a vacuum pump to complete the reaction. Thus, a hydroxyl value of 57 KOHmg / g and an acid value of 0.2 KOHmg / g
g, a polyester diol having a number average molecular weight of 2,000 was obtained.

Preparation Example 5 In a round-bottomed flask similar to that of Preparation Example 1, 1,000 parts of 1,5-pentanediol and 1270 parts of adipic acid were charged, and esterification was carried out at 200 ° C. while removing condensed water under a nitrogen stream. Time went on. The acid value of the polyester is 2KOHm
After confirming that the amount became g / g or less, the degree of vacuum was gradually increased by a vacuum pump to complete the reaction. Thus, a polyester diol having a hydroxyl value of 33 KOH mg / g, an acid value of 0.5 KOH mg / g, and a number average molecular weight of 3,000 was obtained.

Example 1 Into the same round bottom flask as in Production Example 1, 1000 parts of the polyester diol obtained in Production Example 1 and 222 parts of isophorone diisocyanate were charged.
After reacting for a time to produce a prepolymer having a free isocyanate content of 3.34%, 815 parts of methyl ethyl ketone was added to obtain a uniform urethane prepolymer solution. Next, 2037 parts of the urethane prepolymer solution was added to a mixture consisting of 77.0 parts of isophoronediamine, 8.4 parts of di-n-butylamine, 1219 parts of methyl ethyl ketone and 1017 parts of isopropyl alcohol.
The reaction was performed at 0 ° C. for 3 hours. The obtained polyurethane resin solution (hereinafter referred to as resin solution A) has a resin solid content concentration of 3
0%, viscosity was 890 cP / 25 ° C. The number average molecular weight of the polyurethane resin was 39000.

Example 2 The same round bottom flask as in Production Example 1 was charged with 1000 parts of the polyester diol obtained in Production Example 2 and 333 parts of isophorone diisocyanate.
After reacting for a time to produce a prepolymer having a free isocyanate content of 3.00%, 815 parts of methyl ethyl ketone was added to obtain a uniform urethane prepolymer solution. Next, 2148 parts of the urethane prepolymer solution were added to a mixture consisting of 74.9 parts of isophorone diamine, 9.1 parts of di-n-butylamine, 1389 parts of methyl ethyl ketone and 1102 parts of isopropyl alcohol, and then 5
The reaction was performed at 0 ° C. for 3 hours. The obtained polyurethane resin solution (hereinafter referred to as resin solution B) has a resin solid content concentration of 3
0%, viscosity was 820 cP / 25 ° C. The number average molecular weight of the polyurethane resin was 36,000.

Example 3 Into the same round-bottom flask as in Production Example 1, 1000 parts of the polyester diol obtained in Production Example 3 and 203 parts of m-tetramethylxylylene diisocyanate were charged, and heated at 130 ° C. for 6 hours under a nitrogen stream. After reacting to produce a prepolymer having a free isocyanate content of 3.36%, 815 parts of methyl ethyl ketone was added to obtain a uniform urethane prepolymer solution. Next, 76.3 parts of isophorone diamine,
8.3 parts of di-n-butylamine, methyl ethyl ketone 1
2018 parts of the urethane prepolymer solution was added to a mixture consisting of 188 parts and 1001 parts of isopropyl alcohol, and then reacted at 50 ° C. for 3 hours. The obtained polyurethane resin solution (hereinafter referred to as resin solution C) had a resin solid content concentration of 30% and a viscosity of 930 cP / 25 ° C. The number average molecular weight of the polyurethane resin is 420
00.

Example 4 The same round bottom flask as in Production Example 1 was charged with 11,000 parts of the polyester diol obtained in Production Example 4 and 222 parts of isophorone diisocyanate.
For 6 hours to produce a prepolymer having a free isocyanate content of 3.35%.
Five parts were added to obtain a uniform urethane polymer solution. Then, to a mixture consisting of 43.9 parts of 2-methyl-1,3-propanediol and 2137 of methyl ethyl ketone, 2037 parts of the urethane prepolymer solution and 2.0 parts of stannous octoate are added. Allowed to react for hours. The obtained polyurethane resin solution (hereinafter referred to as “resin solution D”) had a resin solid content concentration of 30% and a viscosity of 720 cP / 25 ° C. The number average molecular weight of the polyurethane resin was 26,000.

Comparative Example 1 Into the same round bottom flask as in Production Example 1, 1000 parts of the polyester diol obtained in Production Example 4 and 222 parts of isophorone diisocyanate were charged and reacted at 100 ° C. for 6 hours under a nitrogen stream to obtain a free isocyanate content. After preparing 3.35% of prepolymer, methyl ethyl ketone 815
To obtain a uniform solution of the urethane prepolymer. Next, 2037 parts of the urethane prepolymer solution was added to a mixture consisting of 75.1 parts of isophoronediamine, 11.8 parts of di-n-butylamine, 1221 parts of methyl ethyl ketone and 1018 parts of isopropyl alcohol, and then reacted at 50 ° C. for 3 hours. Was. The obtained polyurethane resin solution (hereinafter referred to as “resin solution E”) had a resin solid content concentration of 30% and a viscosity of 1700 cP / 25 ° C. The number average molecular weight of the polyurethane resin was 29000.

Comparative Example 2 The same round bottom flask as in Production Example 1 was charged with 1000 parts of the polyester diol obtained in Production Example 5 and 203 parts of m-tetramethylxylylene diisocyanate, and was heated at 130 ° C. for 6 hours under a nitrogen stream. After reacting to produce a prepolymer having a free isocyanate content of 3.37%, 815 parts of methyl ethyl ketone was added to obtain a uniform urethane prepolymer solution. Then, isophorone diamine 76.5
Part of di-n-butylamine, 1188 parts of methyl ethyl ketone and 1002 parts of isopropyl alcohol.
Then, the mixture was reacted at 50 ° C. for 3 hours. The obtained polyurethane resin solution (hereinafter referred to as resin solution F)
Has a resin solid content of 30% and a viscosity of 1900 cP / 2
5 ° C. The number average molecular weight of the polyurethane resin was 37000.

(Preparation of ink) Titanium white (rutile type) 3
0 parts, a mixture of a composition consisting of 50 parts of the polyurethane resin solution obtained in Examples 1 to 4 and Comparative Examples 1 to 2, 10 parts of toluene, and 10 parts of isopropyl alcohol, each of which was ground with a paint shaker and white printed. An ink was prepared. To 100 parts of the obtained mixture, 35 parts of toluene and 15 parts of isopropyl alcohol were added to adjust the viscosity, and six white printing inks as shown in Table 1 were prepared. The white printing ink of Comparative Example 3 was obtained by adding 2 parts of isophorone diisocyanate to the ink obtained in Comparative Example 1 to obtain a two-pack printing ink.

(Preparation Method of Laminate Film and Performance Evaluation Method)
15 μm thick corona discharge treated nylon film (N) by a simple gravure printing machine equipped with a gravure plate of
Printed on the discharge-treated surface of Y) and one surface of polyethylene terephthalate (PET) having a thickness of 11 µm, and dried at 40 to 50 ° C to obtain a printed film. 3 g / m ^{2 of} a polyurethane adhesive having a solid content of 25% on the printing surface of the printing film.
After coating and drying with the coating amount of
A laminated film was obtained by dry laminating a μm polyethylene film. The laminate strength (adhesive strength) and the suitability for boiling at 100 ° C. of the thus obtained laminate film were evaluated as follows. Table 1 shows the evaluation results.

Boil aptitude (1) Evaluation by change in appearance of film The appearance change of the laminate film after boiling at 100 ° C. for 30 minutes was observed. 〇-----There is no abnormality in the film. Δ −−−−− A very small portion of the film is delaminated, or blisters are generated with a small amount. C: A part of the film is delaminated or blisters are generated. (2) Evaluation by change in lamination strength (adhesive strength) After boiling the laminated film at 100 ° C. for 30 minutes, it was cut into a width of 15 mm, and a speed of 300 mm was measured with a peeling tester.
The T-peel strength (unit: g / 15 mm) was measured per minute and compared with the strength before boiling.

[0047]

[Table 1]

Claims (3)

(57) [Claims] 1. A printing ink binder mainly containing a polyurethane obtained by reacting a polymer diol, a diisocyanate compound and a chain extender, wherein 2-methyl-
A binder for printing ink, characterized by using 1,3-propanediol. 2. The method according to claim 1, wherein the polymer diol is 2-methyl-1,3-
The printing ink binder according to claim 1, which is a polyester diol comprising a glycol component containing at least 50% by weight of propanediol and a dibasic acid component and having a number average molecular weight of 700 to 4000. 3. The binder according to claim 1, wherein the chain extender contains at least 50% by weight of 2-methyl-1,3-propanediol.